Luminance level

Devices with 10,000 h or more lifetime with parameters measured at luminance levels of 500cd/m2 for red and 1000 cd/m2 for blue and green. 

A slight deviation from the linear relationship was observed at lower luminance levels (<2 cd/m2) in Figure 9.11c. This deviation comes from a fluctuation in /PLed versus FPLed measurement at lower voltages (<2.5 V), where smaller FPLed steps (0.2 V) are applied as shown in Figure 9.11a. 

Table 3.12 Luminance levels for patterned phosphor and colour by white approach (60 Hz)...

Artificial lighting by sealed bulkhead or fluorescent fittings, to provide an overall luminance level of 300 lux ... 

Brightness is the available luminance for each picture element. A typical HMD based on a cathode ray tube (CRT) can display no more than about 400 perceptible luminance levels. Sufficient brightness is particularly a problem for liquid crystal displays (LCD). 

Luminance increased with increasing injection current, and the driving voltage is dependent on the polymer used. Luminance levels of the device using... 

In monochrome video, images of objects are distinguished from one another and from their backgrounds as a result of luminance differences. In order that detail in the picture be visible and that objects have clear, sharp edges, it is necessary that the video system be capable of rapid transitions from areas of one luminance level to another. This degree of resolution need not match that possible in the eye itself, but too low an effective resolution results in pictures with a fuzzy appearance and lacking fineness of detail. 

The information content consists of a combination of luminance and chromaticity information since it describes the distribution of luminance levels and chromaticity values in the picture. 

The information content of a video signal can be broken down into basic component definitions consisting of (1) luminance level, (2) monochrome level, (3) chromaticity value, (4) raster coordinates, (5) point image, (6) line image, and (7) picture element. Various recording, delivery, and playback systems can be developed through the use of the following. 

The luminance level at a given point in a picture is the ratio of the luminance at that point to the maximum luminance occurring anywhere in the picture during an interval in time. Its value is between zero and unity. The reciprocal of the lowest luminance level in the scene is called the contrast level of that scene and the reciprocal of the luminance range is called the contrast range. 

The monochrome level at a given point in a color television image is the luminance level in the monochrome picture, which appears in the absence of the chrominance signal. 

If the waveform monitor has a dual filter mode, the operator can observe luminance levels and overaU ampHtudes at the same time. The instrument switches between the flat and low-pass filters. The Hne select mode is another useful feature for monitoring Hve signals. 

Differential gain (dG) distortion refers to a change in chrominance amplitude with changes in luminance level. The vividness of a colored object changes with variations in scene brightness. The modulated ramp or staircase is used to evaluate this impairment with the measurement taken on signals at different APL points. 

A transport defect at the luminal level of the enterocytes has been suggested for zinc in acrodermatitis enteropathica. 

---